Doorknob construction



Feb. 1, 1955 w, c

DOORKNOB CONSTRUCTION Filed May 20, 1955 4 IN VEN TOR.

VV/LL/HM 6. CHI/v.

HTTO/PNEY.

United States Patent F DOORKNOB CONSTRUCTION William C. Cain, Hartford, Conn., assignor to The American Hardware Corporation, New Britain, Conn., a corporation of Connecticut Application May 20, 1953, Serial No. 356,135

Claims. (Cl. 292-347) This invention relates to a door knob and the method of manufacturing the same, and more particularly to a knob, for door latch operating units and the like, such as fully described in the copending application of Nicholas A. Welch and Frank J. McConnell, Ser. No. 208,743, filed January 31, 1953, and now Patent No. 2,675,692, dated April 4, 1954.

Those parts of the said door knob which embody the present invention are shown in the accompanying drawings in which:

Fig. l is a side view, partly in central horizontal section, showing a door knob and parts of a knurling tool which is used in connection with the present invention.

Fig. 2 is an end view, partly broken away, of the parts shown in Fig. 1.

Fig. 3 is a side view showing portions of the said parts on a greatly enlarged scale to illustrate the present invention.

Fig. 4 is an end view of said parts as shown in Fig. 3.

Fig. 5 is a sectional view on line 55 of Fig. 3.

Fig. 6 is a similar view on line 66 of Fig. 3.

As shown in the said drawings, the numeral 5 denotes the shell-like grip portion of my improved door knob which, as described in said patent, has an annular free edge portion 6 which extends inwardly into an annular groove 7 in the exterior of a collar 8 to secure the said grip portion to the collar.

Several dilferent methods and constructions have been tried for securely connecting the grip portion to the collar in order to prevent relative rotation between the two when a substantial torque was applied to the grip portion as this would present an extremely objectionable defect which would practically destroy the usefulness of the door knob. It has been found that the construction and method provided by this invention are far superior to any other of those tried since they provide a connection in which the two parts are securely interlocked to resist the torque applied thereto.

In accordance with this invention, after the annular free edge portion 6 of the grip 5 has been forced into the annular groove 7 in the collar 8, the said parts are subjected to a knurling operation such as illustrated in the drawings and in which the said assembled parts are rotated in a suitable manner and knurled with a knurling tool using a knurling wheel 9 having sharp edges. The said operation is performed on the rotating grip and collar by forcing the knurling wheel inwardly so that an edge of the wheel will engage the outer surface of the grip portion 5 slightly behind the point where it enters the annular groove 7. Both the grip portion and the surface of the outer end 8a of the collar are simultaneously knurled so that the metal forming the two parts becomes intermeshed as illustrated in the greatly enlarged views 3 to 6 of the drawing. It will be understood from these views that when the knurling wheel is forced inwardly, the sharp corner thereof will scrape the metal from the inner edge of the grip portion, as indicated at 10. This metal is driven into the end 8a of the collar and into intermeshing engagement with the teeth formed simultaneously thereon by the knurling wheel.

The metalscraped from the grip portion and deposited around the end of the collar in the form of the teeth 12 provides an irregular annular flange 11 which is substantially continuous and intermeshes with the teeth on the collar so that the grip portion and the collar are interlocked.

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It will be noted from Fig. 5 that the metal forming the flange 11 extends further along the bottom of each tooth, as shown in Fig. 6, than it does at the top of the tooth, as shown in Fig. 5. This is due to the variation in the amount of metal scraped off of the grip portion by the knulrlling wheel in forming the high and low points of the teet As the metal forming the flange 11 is forced into intermeshing engagement with the teeth 12 being formed on the collar, it displaces the metal of the collar which causes the formation of a spur 13 under the high and the low point of each tooth which is forced into the free edge portion 6 of the grip, as indicated in Figs. 5 and 6, to cause a further interlocking of the two parts.

By the use of the improved construction and the method provided by my invention, a door knob is produced in which the shell-like grip portion'5 is interlocked with the collar member 8 against both rotational and longitudinal movement relatively thereto and the said interlocking of the two parts is rendered strong and durable by reason of the irregularities which are caused in the formation of the projected annular metal portions 11 and 13 of the grip portion and sleeve, respectively.

In actual tests made with door knobs manufactured in accordance with the present invention, it was found that the connection between the grip portion and the collar would resist up to one thousand inch pounds of torque. It will, therefore, be understood that by my present invention I have provided a novel and highly important method of securing a shell-like grip portion to a cooperative part whereby a strong and durable connection is provided with an operation that is highly economical.

I claim:

1. A door knob construction including a collar having an annular groove in its outer surface, a shell-like grip member having an annular free edge portion extending inwardly into said groove and thereby securing the grip member to the collar against longitudinal movement relatively thereto, and a series of teeth on said collar including meshed portions of the grip member and collar for preventing rotational movement of the grip member relatively to the collar.

2. A door knob construction including a collar having an annular groove in its outer surface, a shell-like grip member having an annular free edge portion extending inwardly into said groove and thereby securing the grip member to the collar against longitudinal movement relatively thereto, and a series of teeth extending longitudinally over meshed portions of said collar and grip member and forming annular irregular ridges extending in opposite directions and thereby interlocking the grip member to the collar against rotational movement relatively thereto.

3. A door knob construction including a collar having an annular groove in the surface thereof, a grip member in the form of a shell having an inwardly turned annular free edge portion extending into the said groove to secure the shell to the collar against longitudinal movement relatively thereto, adjacent outer portions of said shell and collar having a series of longitudinally extending teeth including meshed irregular annular ridges formed by portions of said shell and collar and extending in opposite directions and thereby securing the shell to the collar against rotational movement relatively thereto.

4. A door knob construction including a collar having an annular groove in its outer surface, a grip member in the form of a shell having an annular free edge portion extending into said groove and thereby securing the grip member to the collar against longitudinal movement relatively thereto, and a series of longitudinally extending teeth including adjacent portions of said shell and collar forming an irregular annular flange extending outwardly from said shell along the outer surfaces of the teeth and an annular row of irregular projections extending from the collar into the shell below the surfaces of the teeth; the said flange and projections preventing rotation of the shell relatively to the sleeve.

5. A door knob construction including a collar having an annular groove in its outer surface and a grip member in the form of a shell having an annular free edge portion extending into said groove and preventing longitudinal movement of the shell relatively to the collar, the said collar having an end portion projecting longitudinally beyond the groove and exteriorly of the shell, :1 series of longitudinal teeth extending around the outer surface of the said end portion of the collar, the said teeth including meshed portions of the shell forming an irregular annular flange extending longitudinally from the shell and into the teeth along the outer surfaces of the collar, and an annular row of irregular projections on the collar extending therefrom inwardly into the groove and being imbedded in the said free edge portion of the shell below the outer surfaces of the teeth whereby the said shell and collar are interlocked to prevent rotational movement of the shell relatively to the collar.

References Cited in the file of this patent UNITED STATES PATENTS 447,266 Wilrnot et al Feb. 24, 1891 1,711,209 Robb Apr. 30, 1929 2,004,387 Dewald June 11, 1935 2,095,885 Moreira et a1. Oct. 12, 1937 2,590,229 Card Mar. 25, 1952 

